Microbiology Exam 3

Question 1

Lysogenic Phage

Answer 1

• provides immunity from other phages
• some offer bacterial pathogenesis
• will only kill the host when it’s about to die anyway

Question 2

prophage

Answer 2

-phage DNA in the lysogenic state

Question 3

lysogen

Answer 3

a bacterium harboring the prophage

Question 4

transcriptional antitermination

Answer 4

-termination of mRNA transcript that needs to be repressed to get a complete set of transcripts for making proteins

Question 5

Development Stages

Answer 5

• early stage: uses antitermination protein N to regulate hte synthesis of recombination and replication functions
• later stage: uses antitermination protein Q to regulate the synthesis of its late proteins including head and tail proteins

Question 6

PL and PR

Answer 6

• initial promoter regions for transcription
• outward from immunity region
• encodes Cro protein and N protein

Question 7

Cro protein

Answer 7

-an inhibitor of repressor synthesis (CI)

Question 8

N protein

Answer 8

-antitermination factor that permits RNA pol to bypass the transcription termination sites

Question 9

nutR

Answer 9

• N utilization rightward
• a sequence in RNA that provides a recognition for the N protein to bind and interact with RNApol
• bring together antitermination complex (Nus involved)
• resistant to almost all types of transcription termination signals

Question 10

tR1

Answer 10

-transcription through tR1 encodes for replication proteins

Question 11

Q protein

Answer 11

-antitermination protein that turns on transcription of late genes

Question 12

nut site

Answer 12

• 3 boxes
• Box B: forms a hairpin structure that is recognized by the N protein
• then conformation change that allows RNApol to bind
• Box A and C are nonessential but stabilize

Question 13

N-nut-RNApol complex

Answer 13

-nusA, nusB, nusE, and nusG stabilize complex and facilitate antitermination past tR1